Syringe with adjustable piston construction



Feb. 12, 1946. G. N. HEIN 2,394,687

SYRINGE WITH ADJUSTABLE PISTON CONSTRUCTION Filed June 21, 1941 2 Sheets-$heet l 249. 23% \Zidj 28$ M a 4 INVENTOR.

GEORGE 1V. HE/N A TTORNEY.

Feb. 12, 1946. N, HEIN 9 SYRINGE WITH ADJUSTABLE PISTON CONSTRUCTliON Filed June 21, 1941 2 Sheets-Sheet 2,

INVENTOR. Graze: 1V. HE/A/ Patented Feb. 12, 1946 UNITED STATES PATENT OFFICE SYRINGE WITH ADJUSTABLE PISTON CONSTRUCTION 'GeorgeN. Hein, San- Carlos, Calif.

Application June'21, 1941, SerialNo. 399,094

(Cl. 1282l5) Claims.

vide'apiston simple in construction in which a gasketor packing means may be adjusted remotelytherefrom and at any position during the excursion ofthepiston in a cylinder or barrel; another object is to provide ajpiston'assembly which maybereadily removedv from the cylinder or barrel while still maintaining its adjustment with relationto'tlie cylinder; another object is to provideapiston in which the partsmay be dis-assembled from their operating relationship and yet remain loosely connected or linked relative'to each other to avoid complications of reassembly into their previously adjusted operative relationship. A further object isto provide .a

piston which maybe quickly and easily adjusted to fit cylinders of varying diameters, and to provide in connection therewith a readily adjustable packing gasket having great sealingqualities with relation to the cylinder with a minimum of frictional resistance.

With the foregoing andother objectsin-view, all of which will be more apparent as this dosoriptionproceeds, the invention is exemplified in a practicaland efficient form in the novel construction and combination of partshereinafter described, illustratedin the accompanying drawings, 'andpointed ou-tin the claims hereto appended, it being understood that various changes in-the form,-proportion, size and details of construction of the apparatus may be resorted to within thescopeof the appended claims without departing'from-the spirit or sacrificing'any oi the advantages of the invention.

To moreclearly comprehend the invention, ref

erence is directed to the accompanying drawings wherein:

Fig. 1 is a longitudinal view of oneform which the invention: may take, partly broken away and partly in transverse section.

Fig. 2-i's a longitudinal side view of portions of structure shown in Fig. l, the parts thereof being in operativelydisassembled positions, and the view being partly insection and partly bro'ken away.

Fig. 3 is-a top view of a'sleevemember shown in Figs. 1, 2 and 5.

Fig. 4-is a lateral transverse sectionon line Fig.5 is a:longitudinaltransverse sectionof a modified form of a device ofthe invention.

Figafiis a longitudinal transverse section of ancther modified form of the invention.

Fig. '7 is a fragmentary.longitudinalview partly broken away, of avportion of the device shown in:Fig.""6,' to. show detail.

'Fig.*8 is*a fragmentary longitudinal view of a portionoi apparatus :shownin Fig. "6, enlarged to show detail. I

Fig. 9 is an end viewof 'a guide member shown in Fig. 8 and showing apiston rodmember partly in section.

.Referring: to Fig. l, there is provided a cylinder 01' syringe barrel I'll open atone end- II to receive a pistonandhaving an opening 12 of reduced diameter at'its opposite end'for dischargeof'fluid within the barrel" responsive to'pressure, .or the filling of the barrel upon thesuction stroke of the piston.

A piston member generally indicated l3 isprovided, and preferably comprises an elongated sleeve member! which ishollow or tubular to permit a piston rod 122 to pass t'herethrough; more particularlyit is preferredthat the tubular sleeve member M be generally cylindrical in "transverse section having its side walls fenestrated as at IS. The elongated sleeve M is capped at its upper end by the cap '6, the latter having aslotted opening I! at its edgeand'extending inwardly to include the axisof the .sleeve *asbes't shown in Fig. 3. The radiallyzouteriopening of the slot I! communicates withone of the fen'estrations IS in the side of the elongated sleeve member. The slotted cap member I6: is concave centrally as at l8 and provides a seat for :rotatively seating of a thumbnut hereafter described.

The opposite or'bottom end of theelongated sleeve is likewise closed "by a suitable member such as a plate I9 which has a beveled gasketcontacting face i9 and is.provided With a centrally'disposed opening 20 having upwardly and inwardly tapered Walls 2! for receivingand accur-ately centering an extended portion of agasket relative to the piston and also providing a holding means to-prevent the movement of the gasket away from co-axial alignment with the rod"22 Whichmight cause its sealing wall to vault past'the retaining "face of the plates]! and when-under pressure or suction. Apiston rod 22 is mounted longitudinally within the sleeve [4, one end of which is releasably engaged in the slot H of the cap member l6 and the opposite end of which passes through the opening 20 of plate l9.

Means are provided for reciprocating the piston assembly in the syringe cylinder, and for adjusting a packing gasket member at the opposite end thereof. Without limiting such means to the specific exemplification herein, there may be conveniently provided on piston rod 22 a threaded end 23 threadedly engaged by a member for hand pressure broadly referred to herein generically as a thumb nut or pressure member 24, meaning thereby, any shape or form of member for manipulation to reciprocate the piston I3 or adjust a packing gasket 26. As shown in Fig. 1, the thumbnut has a convex base 25 which rotatably seats into concavity 18 of the cap l6 so as to center the piston rod 22 and also to establish it in a fixed, though releasable, position relative to the sleeve 14 when the thumb nut is tightened on threads 23.

The opposite or lower end of the rod 22 is provided with a fixedly attached disc plate 28 beveled on its inner face 29. The bevels of plates i9 and 28 converge relatively toward their cen ters as illustrated in Fig. 1. The opposed faces of the plates are of very substantial diameter so as to back-up or reinforce the planar faces of the gasket adjacent the sealing edge. the beveled faces of plates l8 and 28 there is mounted gasket member 26 which is of compressible material such as rubber, leather, combinations of rubber and fabric or the like, the quality of resilience of rubber being preferred for both compressibility, and radial expansion and contraction. The upper portion of the gasket, as shown in Figs. 1 and 2 comprises a conical frustrum 26 which fits into the circular converging walls 2| of the opening 28 in the sleeve, thereby centering both the gasket and the rod 22 upon which it is mounted. The side or sealing wall of the gasket is tapered from the upper and lower planar faces of the gasket to a substantially median plane indicated by line A laterally transversely of the gasket body providing a circumferential apex 2'! in the gasket sealing wall. The beveling of the oppositely disposed faces I9a and 29 of the respective sleeve and disc plates l9 and 28 provides faces or converging walls between which the body 26 of the gasket is disposed when the apparatus is in operating position as shown in Fig. 1. The purpose of having such converging walls is so that upon manipulation of the thumb nut member 24 rotatively on the concavity 18 of the seat, and relative to the threaded portion 23, the gasket will be clampingly compressed between the bevels of plates I9, 28 and thus expanded radially due to its compressibility so that the circumferential apex 21 will contact the inner wall of the cylinder barrel in any degree desirable or necessary to effectuate the degree of sealing desired by the operator. Though it is much preferred that the plate faces 19 and 29 be beveled, it has been found sufilcient for fairly efficient operation if the bevel is omitted, or if the bevel is included in one only of the faces 19 25, in which latter event it is preferred that the face 29 of the plate 28 should be the selectively beveled plate.

The piston assembly l3 may be Withdrawn at any time from the cylinder as a unit as shown in Fig. 2 in which event the unit may be brokendown for purposes of cleaning or sterilization by merely tilting the thumbnut member 24 from Between the concave seat I8 since the outer edges of the slot I! are beveled as at H, whereupon the piston rod 22 may slide radially outwardly through the opening of slot IT and into the communicating fenestration l5, and thus be disassembled from an operating position and yet remain linked together loosely and without relative stabilization, because the rod 22 is held in the opening 20 since thumbnut 24 and asket 26 are wider in diameter than opening 20. This releases the members [4, 22, 26 and 28, loosely and without fixed relative stabilization for sterilization and without disturbing their previous rela' tive adjustment when reassembled.

After the device has been cleaned or sterilized it may be quickly and accurately reassembled into operating position by drawing the conical portion 2b of the gasket into the tapered opening 20 and snapping the convex surface 25 of the thumbnut 24 over the beveled ed e I! of the cap l6, the rod 22 passing into the slot IT in so doing, the compressibility of the gasket member 26 with relation to the faces I! and 29 being suilicient to permit such snap-over movement.

An especially advantageous result is accomplished by the structure herein above described and its demountability and its remountability while its parts remain linked, in that when the piston rod is dismounted it has an extendability independently of the means which normally holds the piston rod 22 relative to the tubular member 14. This is highly desirable so that the piston rod, the gasket thereon and the tubular member remain loosely linked together for sterilization and quick reassembly. In other words, in Fig. 2 the means that normally holds the piston rod 22 relative to the tubular member l4 in syringeforming relation is the thumbnut 24 and the concave seat [8. This holding means may be totally dismounted or relatively disconnected as shown in Fig. 2 and yet the sleeve, rod and gasket remain linked together and the rod has an extendability independently of the holding means. Stated in terms of operation, the resilience of the gasket 26, or a single turn of the thumbnut on the threads I6 will permit the dislodgement oi the thumbnut from the seat, yet the rod 22 has an additional extendability totally independently of these means which normally hold the tubular member l4 in operative piston-forming relation, while the parts remain linked together for quick and accurate reassembly.

In the modification of Fig. 5 the piston rod 22 is divided into two sections one of which is fixedly mounted as by threads and pin 24 in the thumbnut 24 and is rotatable thereby, said section being of relatively shorter length than in the device of Fig. 1. At the opposite end, the said section of the piston rod 22 has a threaded connection 23 to a separate section of the piston rod whereby a lower plate member 28 i drawn into or released from a compressing relation upon the longitudinally central body portion of gasket 26 to selectively radially expand or radially contract the circumferential apex or sealing edge 21 by substantially similar operation as explained in relation to the device in Fig. 1. However, in the modification of Fi 5, the plate 28" is embedded in the body of the lower portion of the gasket 26 and thereby provides a cushioned buffer portion 26 between the plate 28 and the syringe body I0 which is desirable in some instances wherein the syringe bodies are made of glass.

ramps? :3

Q'Ihelixmer wall 2 I a of .the .centralzropening .720

of lower :closurexplatell9 of the pistonsassembly d3 is'.tapered at:the lower portion-for apart only gasket thereon, the gasket is permanently centeredrrelative to the piston-rod, and therefore: it requires only a very shorttaperedengagement 'of the conical wall of the gasket frustrum 26 and the beveled wall portion 2l to accurately axially alignthe gasket 26 with'the-piston as- 'sem'bly I93. easier adjustment of the :gasket and is preferably used in larger devices. The cap 16 of the 1' piston assembly in Fig. is concave and radially This construction "makes "possible slotted similar to cap'l6'in"Figs.'1,"2 andi 3,-;.the slot I l likewise connecting witha fenestration lfi "of the sleeve: l 4; which permits demountabiiityi of t'hepiston rod'in the same manner as showniinzi Fig. 2.

In Fig. '6 another modificationl'of theinvention -is disclosed for that type of syringe which is: usually of relatively vlarger diameter, 'comprisingla barrel cylinder machined at its lower end to securely or threadedly mount a discharget'nipple "36. At the opposite end is a finger gripping. yoke .31 threadedly mounted to the cylinderias at .38.

The yokel37 has a pin 31 which, duringsassembly, is guided through an entering slot 3l .one face of the-slot being shownin Fig. :fiinrthe 'piston sleeve 40 atthe upper end of the;ifenestration 4|.

This pin 3! prevents the apiston from revolving when axial rotationtis imparted to adjusting finger engaging :thumbnut 'memgitudinal fenestrations 4| within one of-zwhich the pin 31* may slide. The pistonsleeve-xlorotatively mounts at its upper end at seat 410 1a 'thumbnut 42 which "has fixedly mountedtherein for rotation therewith :a tubular .guide r member :43 which has an axial opening 4:3;at -.its1-lower end, including a radial communicatingcslot flb.

To the lower end of the sleevelfl-thereiisaffixed aclosure disc plate member .46 providing at its outer face a plate having:a zbeveledzcontacting face wall'4'1, to contactia gasket 48, the

disc plate '46 having an axial opening oem trally thereof, said axial openingzhavingazradially outward communicating slot 46'. fAlpiStOn rod 44 is slidingly engaged through theopenings '43 and 46 which are-co-axial, xsothat innssembly or disassembly, the'piston-roid 44 randg'pin 5| maybe'passed through the two openings 2439, 46 whereupon the upper threaded endiof :rod :44 may be releasablyithreadedly engaged zas at by the'fixedly held end ofiguide member-43in the thumbnut. The piston rod -44 has=a1plate 49 at its extreme end having. a-bevelito: its gasketcontacting face 50, the gasket member 1148 being disposed between said-tworhereledzfaces #41 and '50 the bevels of'which relatively convergetoward the center thereof.

.The radially outward circumferentialsealing wall of the gasket 48 may be-.bev.eled:outwar.dly from bothof the planar gasketfaces which-contact said beveled plates, so as to providea rcircumferential sealing edge or apex to -.-the sealing wall on a median transverse planeAas similarly shown in Fig. 2. The plate 49ofthe piston-rod '44 is drawn into, or released from compression 7.0 :hangoon the piston sleeve 40.

itlmmbmut which, :due :to the relatively. fixed insurrection;-stherebmrdtates-griide member 43 upon :athreads JI'he :thumbnut 42=seats rotatively on :collar of pistonrmember [was shown at 40*.

piston assembly isreleasable so as to clean :ior, sterilize iits-vparts, by disengaging the threads 45 from :gui'desmember 4'3, whereupon the associatedpartsz'mayitbe disassembled from operative itrelatronship but :remain .loosely connected :or

53m :lirxked sass-further :described .hereafter. To more tclearlyiexemplify the releasing mechanism of rod 44 vwith'relationztoiguide member .143, it 'will'be "noted :that"rod 44 has a peg or :pin .5I inter-- -mediate its -cnds. rAlso, thereis; provided atithe if-ree-wendofcguide 43,:a'tubular insert plug 56 a-which is-Tfixedlyxsecured within the tubular end of guide memberafl, "the inner diameter of plug 66 being that of the piston rod 44 for whichit ialfords a i longitu'dinal slide "bearing, while the onterr'diametert'fits snuglya into the t'tubular guide sleeve '43. The itibase of the plug fifi provides the eopeningsfli i and slot 43 and its lower circumferentialaportionr providesra shoulder'fifl affording eaasoat inrontactzwithrthe lowerpend ofathe wall 2.25 iofazthe'ltubularzguideimember .43.

lateitstupperaendrthe plug-iifi'is cutaon an; angle 10f 'zaxhelix ;providing :tan end edge "53, thus leaviingrayspace betweenzthe innerwall ofnguide mem- :-ber'=;43;:and- .the;outer circumference of piston rod 5530 :44,-mhich:givesrroom :for peg :5! to :rotate and slide :free'ly vwithin the guide 43. At the lower tportion :o'fxthe rhelicaleedge-53 of insert plug ;66 zit iis irregularly :slotted :transversely and then :axiallyras watz 52 affording :a bayonet 1 slot having I :afdepressioniSZPor aitemporary stop for pin 5|,

i-thuszloosely linkingnthetubular member 40, rod 44,: gasket lasandgplates :46, 49 when the parts .-:are ioxtemied 1 for-cleaning orssterilizing. It will 'beznbservedrthat;thisaembodiment in Figs. 6 to 9 40 :isithessamens ahasbeenheretofore described with :relatiomto Fig. 2,-in:tbat thejholding means of :the piston "rod assembly relative .to the tubular ssleevmmember-lfl is the seat 340 and the'thumbrnutiflgyetvwhencthe thumbnut iscompletely un- 45 seatedzrflhdqdiscohnected, an extension of rod :44

mayxbe effected, and yet thetubular member, guideimemberd3,;gasket-148 and plates 46 and 49 remain loosely linked independentof: the thumbmzltf42zanfdzseat tll wherebythe'rod-has an inde- =5u endent -.extendabllity. However, to completely memo ve therpistonrod 44, it may be rotated so lthelpinzfil mayapass through-the mouth of the zbayonet sloti52-whereupon the piston rod 44 can :heacompletelymemoved by :pin 5| passing out 65.5 through opening143 'ilmassemble the syringe shown in Fig. 6, the operator wouldifirst'pass the fenestrated piston sleeve- 4| :through-the finger ring yoke 31 by en- .teringithegpin .31 into-sl0t 31 (-see Fig. 7), to

60 allowpin :3T-.t0--s1ip into the fenestration 4i then the piston rod :44, having gasket .48 mounted thereon would ;be inserted through the openings 'fl zand .43 and :threadedly connected to the thumb-nut -42, finally'screwing the yoke}? on $5 the'ssy-ringecbairel. =To disassemble thesyringe .foracleaning-and sterilizing. the operator would first. pulhthe piston assembly, 43, 44 out about mlfaway, iunscrew the yoke. 31 and complete the removalof 'piston-assembly, allowing the yoke to Then, by looseningzthethumbrnut 42 from threads 45 and thus iiisconnecting the parts of the piston assembly .fromatheir ioperatingirelationship, he would have all parts tremain .-'loosel y,in Jone linked assembly of gasket 48 by rotative manipulation :of :26 thatfiwmlldEbezsterilizable. .In-thisponnection it will be noted that upon disconnecting the piston rod 44 from its threaded engagement 45 with thumbnut 42, the rod 44 would be free to move in opening 43 of the closure plug 66 and would normally drop until the pin 5| contacted the helical edge or ledge 53 which would guide the pin 5i into the oifset 52 of bayonet slot 52 where it would normally be held against inadvertent removal. This action would also drop the plate 5|] away from engagement with gasket 48 so the gasket would freely ride upon the lower extended part of rod 44 and out of contact with plate 46. In this loosely linked, but relatively unstabilized relation, the parts would be sufficiently separated for complete sterilization, yet connected in a loosely linked relation for ease in readily reassembling in operative relationship as a syringe.

Having thus described my invention, I claim:

1. In a syringe, a piston construction comprising a tubular sleeve for sliding axially relative to a syringe barrel wall, said sleeve having a side wall opening and having at one end a plate which has a central opening therethrough and havin at its opposite end a radially slotted seat for a thumbnut, the slot of said seat being in relative communication with the opening in the side wall of the sleeve, a thumbnut rotatively mounted on said seat, a. piston rod in the sleeve extending through said sleeve plate opening, said piston rod having one end adapted for engagement within the slot of the seat and for connection to the thumbnut and having at its opposite end another plate beyond the said sleeve plate opening, an axially compressible and radially expansible gasket mounted on said piston rod between said plates and adapted for sealing against the syringe barrel wall, the said thumbnut and piston rod being threadedly connected whereby the said plates may be adjusted relative to the gasket for selectively radially expanding and contracting the gasket, and said piston rod being selectively movable within said radial slot of the seat and the side wall opening of the sleeve whereby the thumbnut may be unseated while remaining connected to the piston rod and the rod may be loosely extended to release the gasket from its clamped relationship between the plates.

2. In a syringe, a piston construction comprising a tubular sleeve for sliding axially within a syringe barrel wall, said sleeve having a side wall opening and having at one end a plate which has a central opening therethrough and having at its opposite end a radially slotted concave seat for a thumbnut, the slot of said seat being in relative communication with the opening in the side wall of the sleeve, a thumbnut having a convex base face for rotatively mounting on said seat, a piston rod in the sleeve extending through and slidable in said sleeve plate opening, said piston rod having one end adapted for engagement Within the slot of the seat and for connection to the thumbnut and having at its opposite end another plate beyond the said sleeve plate opening, an axially compressible and radially expansible gasket mounted on said piston rod between said plates and adapted for sealing against the syringe barrel Wall, the said thumbnut and piston rod being threadedly connected whereby the said plates may be adjusted relative to the gasket for selectively radially expanding and contracting the gasket, the said piston rod being selectively movable within said radial slot of the seat and said side wall opening of the sleeve whereby the thumbnut may be unseated while remaining connected to the piston rod and the rod may be loosely held in the side wall opening of the sleeve to release the gasket from its clamped relationship between the plates, and the 5 said sleeve, piston rod, thumbnut and gasket being loosely and connectedly linked together in a relatively unstabilized inoperative relation when said thumbnut is unseated from its pistonforrning relation with the sleeve.

3. In a syringe, a piston construction comprising a tubular member for sliding axially relative to a cylinder barrel wall, and having at one end a gasket receiving plate which has a central opening therethrough, said tubular member having at its opposite end a seat for a thumbnut, a thumbnut rotatively mounted on said seat, a piston rod in the tubular member extending through said central plate opening and slidable therein, said piston rod having one end adapted for connection to the thumbnut and having a gasket engaging plate at its opposite end beyond said central opening of the other plate, an axially compressible and radially expandible and contractible gasket mounted on said piston rod between said platcs and adapted for sealing against the cylindrical barrel wall, said gasket having a body portion provided with planar faces for abutting said plates and having intermediate its said faces a relatively narrow circumferential apex sealing edge of greater diameter than said planar faces, at least one of the opposed gasket-contacting faces of said plates having tapered relationship whereby the space between said opposed faces increases from their central portion toward their peripheral edge, the said thumbnut and the piston rod being threadedly connected whereby the said plates may be adjusted relative to the gasket for selectively expanding and contracting the gasket radially, and means for holding the tubular member, the piston rod and gasket in dismounted loosely linked relation whereby the piston rod may be extended to release the gasket from contact between said plates while maintaining the tubular member, rod and gasket in loosely 45 linked relation, said last mentioned means being independent of the means which is operable for radially contracting and expanding the gasket. 4. In a syringe having a cylindrical barrel wall,

a piston construction for sliding axially relative to the cylinder barrel wall, comprising a tubular member having at one end a gasket-receiving plate which has a central opening therethrough and having at its opposite end a seat for a thumbnut, a thumbnut rotatively mounted on said seat, a piston rod in the tubular member adjustably connected at one end to the thumbnut and having a shank extending through and slidable in said central plate opening and having another plate at its opposite end beyond the central opening of said first mentioned plate, a gasket mounted on said piston rod between said plates and adapted for sealing against the cylindrical barrel wall, said piston including means for radially expanding and contracting the gasket, and means for holding the tubular member, the piston rod and gasket in dismounted loosely linked relation, whereby the piston rod may be extended to release the gasket from contact between said plates while maintaining the tubular member, rod and gasket in loosely linked relation, said last mentioned means being independent of the means which is operable for radially expanding and contracting the gasket.

5. In a syringe, a piston construction comprising an elongated tubular member for sliding axially relative to a syringe barrel, and including a thumbnut for finger manipulation at one end, the opposite end of the tubular member including a plate having an opening centrally thereof adapted for receiving therethrough a piston rod for a sealing gasket, a piston rod for passing axially centrally through a gasket and having a transverse plate at its end, said rod being of substantially lesser diameter than the central opening of the plate of the tubular member, said plate members having relatively opposed faces at least one of which has its said opposing face beveled radially outwardly and away from the opposing face of the other plate member, an axially compressible gasket member mounted on said rod having its opposite planar faces engageable between the said respective plates of the tubular member and rod member, said gasket having a circumferential sealing edge tapered from its planar faces to an apex and being provided with a longitudinally axially extending body portion adapted for entering the central opening in the plate of the tubular member, said gasket-mounting piston rod and said thumbnut having threaded connection therebetween for relatively adjusting the plates axially whereby pressure of the plates on the gasket may be varied for selectively expanding and contracting the gasket radially, and means for holding the tubular member, the piston rod and gasket in dismounted loosely linked relation, whereby the piston rod may be extended to release the gasket from contact between said plates while maintaining the tubular member, rod and gasket in loosely linked relation, said last mentioned means being independent of the means which is operable for radially contracting and expanding the gasket.

GEORGE N. HEIN. 

